Electrical components in many different applications utilize flexible printed wiring cables, or “flex” cables, such as cables for electrical power, digital signals, and radio frequency signals. For example, electronic packaging of complex hardware utilizes flex cables to connect various components within the volume allowed. These cables may be bent once during manufacturing in order to fit into a required space and then remain in that bent shape during operation, such as cable components used in commercial electronics, aircraft systems, automotive applications, engine compartments, power plants, sensor equipment, and many other applications. In other applications flex cables connect components through a hinge or other moving part that subjects the cables to repeated bending during operation, such as flex cables in laptop computers, cell phones, and automobile doors. The term “ribbon cable” may also be used in some cases to refer to these printed circuit flex cables.
Flex cables are subject to two types of high-temperature conditions. The first is high temperatures during operation. For example, a flex cable may connect to a sensor that is placed in a high temperature compartment or in close proximity to a very high temperature component. The second is high temperatures experienced during a manufacturing process. For example, a flex cable may undergo a high-temperature soldering process to attach sensitive electrical components to make the flex cable assembly.
Preventive measures typically must be taken to prevent these high temperature conditions from causing the cable to buckle and delaminate, with the cover portion of the cable separating from the rest of the cable and creating an opening or void. This delamination exposes the conductor or other components inside the cable to environmental hazards that can cause permanent failure. Therefore, flex cables are often limited to applications in which the manufacturing and/or operating temperature remains under a maximum temperature, to prevent the cable from delaminating. The radius of curvature of the flex cable may also be kept above a minimum radius, limiting the flex cable to large-radius curves in order to reduce the amount of compressive stress in the cable and prevent buckling at high temperature conditions.
Accordingly, there is still a need for a flex cable that tolerates high temperature manufacturing and/or operating conditions without delaminating.